Problem: A rectangle is $3$ centimeters long. The rectangle is also $5$ centimeters wide. What is its perimeter?
Answer: $3\text{ cm}$ $5\text{ cm}$ The perimeter is the total length of all the sides of the shape added together. Add up the lengths of the sides: $ \text{perimeter} = {5} + {3} + {5} + {3} $ $ \text{perimeter} = 16\text{ cm} $